ABOUT

This is a demo kernel module which demontrates my skills  in creating KLM.
Module intented to emulating rtc device. Time represent in epoch unix
seconds. Module was testing on 3.16.0-4-amd64 kernel only.

Principle:
    * Time parameters(secs, usecs) inits by current system time.
    * Main thread wait 1 second after that incrementing time parameters on
      1 * speed/speed_factor value. Speed_factor = 100, defined in sources.
    * If random mode on increment changes to 1 * rand_speed/speed_facror.
      Where random_speed takes from range equals [0:random_bound].

Parameters of module is:
@param time_sec - unix seconds. Inits from system clock.
@param time_usec- useconds. Inits form system clock.
@param speed          - speed of time flow in module. Values of speed begins 
                        at 100, it means 100 - normal flow, like system 
                        clock, if speed greater - time flow in that module
                        accelerated, if lesser slowing down.
@param random         - if non-zero, current time ascending by increment
                        makes from @random-bound param, interprets like  
                        high border of range of possible values of speed.
@param random-bound   - high border range of possible values of speed in
                        random time mode. Low border is 0.

Module could be inserted and removed from kernel space dinamically. 
Module registers in file /dev/rtcN you can interoperate with it by hwclock
utility. 
Module have interface with userspace in /proc/rtcmodule. You may passing
parameters by string commands:
"s [value]" - sets speed to value; value must be non-negative
"r [value]" - sets random mode if value is non-zero, disable random mode
              otherwise.
"b [value]" - sets high border of distribution range of speed for random mode.
"t [value]" - sets epoch time secs in module.
"u [value]" - sets epoch time usecs in module.

Or reading from that file. outputed:
  Module uptime.
  Difference between sys clock. (Negative means rtc module time ahead sys clock.)
  Speed.
  Random. 1 means on, 0 off.
  Random bound.
  Secs.
  Usecs.